org.postgresql

Class Driver

java.lang.Object

org.postgresql.Driver

All Implemented Interfaces:

Driver

public class Driver
extends Object
implements Driver

The Java SQL framework allows for multiple database drivers. Each driver should supply a class that implements the Driver interface

The DriverManager will try to load as many drivers as it can find and then for any given connection request, it will ask each driver in turn to try to connect to the target URL.

It is strongly recommended that each Driver class should be small and standalone so that the Driver class can be loaded and queried without bringing in vast quantities of supporting code.

When a Driver class is loaded, it should create an instance of itself and register it with the DriverManager. This means that a user can load and register a driver by doing Class.forName("foo.bah.Driver")

See Also:

PGConnection, Driver

Constructor Summary

Constructors

Constructor and Description
Driver()

Method Summary

Modifier and Type	Method and Description
boolean	acceptsURL(String url) Returns true if the driver thinks it can open a connection to the given URL.
@Nullable Connection	connect(String url, @Nullable Properties info) Try to make a database connection to the given URL.
static void	deregister() According to JDBC specification, this driver is registered against DriverManager when the class is loaded.
int	getMajorVersion()
int	getMinorVersion()
Logger	getParentLogger()
DriverPropertyInfo[]	getPropertyInfo(String url, Properties info) The getPropertyInfo method is intended to allow a generic GUI tool to discover what properties it should prompt a human for in order to get enough information to connect to a database.
static SharedTimer	getSharedTimer()
static String	getVersion() Deprecated. use getMajorVersion() and getMinorVersion() instead
static boolean	isRegistered()
boolean	jdbcCompliant() Report whether the driver is a genuine JDBC compliant driver.
static SQLFeatureNotSupportedException	notImplemented(Class<?> callClass, String functionName) This method was added in v6.5, and simply throws an SQLException for an unimplemented method.
static @Nullable Properties	parseURL(String url, @Nullable Properties defaults) Constructs a new DriverURL, splitting the specified URL into its component parts.
static void	register() Register the driver against DriverManager.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Driver

public Driver()

Method Detail

connect

public @Nullable Connection connect(String url,
                                    @Nullable Properties info)
                             throws SQLException

Try to make a database connection to the given URL. The driver should return "null" if it realizes it is the wrong kind of driver to connect to the given URL. This will be common, as when the JDBC driverManager is asked to connect to a given URL, it passes the URL to each loaded driver in turn.

The driver should raise an SQLException if it is the right driver to connect to the given URL, but has trouble connecting to the database.

The java.util.Properties argument can be used to pass arbitrary string tag/value pairs as connection arguments.

• user - (required) The user to connect as
• password - (optional) The password for the user
• ssl -(optional) Use SSL when connecting to the server
• readOnly - (optional) Set connection to read-only by default
• charSet - (optional) The character set to be used for converting to/from the database to unicode. If multibyte is enabled on the server then the character set of the database is used as the default, otherwise the jvm character encoding is used as the default. This value is only used when connecting to a 7.2 or older server.
• loglevel - (optional) Enable logging of messages from the driver. The value is an integer from 0 to 2 where: OFF = 0, INFO =1, DEBUG = 2 The output is sent to DriverManager.getPrintWriter() if set, otherwise it is sent to System.out.
• compatible - (optional) This is used to toggle between different functionality as it changes across different releases of the jdbc driver code. The values here are versions of the jdbc client and not server versions. For example in 7.1 get/setBytes worked on LargeObject values, in 7.2 these methods were changed to work on bytea values. This change in functionality could be disabled by setting the compatible level to be "7.1", in which case the driver will revert to the 7.1 functionality.

Normally, at least "user" and "password" properties should be included in the properties. For a list of supported character encoding , see http://java.sun.com/products/jdk/1.2/docs/guide/internat/encoding.doc.html Note that you will probably want to have set up the Postgres database itself to use the same encoding, with the -E <encoding> argument to createdb.

Our protocol takes the forms:

  jdbc:postgresql://host:port/database?param1=val1&...
 

Specified by:

connect in interface Driver

Parameters:

url - the URL of the database to connect to

info - a list of arbitrary tag/value pairs as connection arguments

Returns:

a connection to the URL or null if it isnt us

Throws:

SQLException - if a database access error occurs or the url is null

See Also:

Driver.connect(java.lang.String, java.util.Properties)

acceptsURL

public boolean acceptsURL(String url)

Returns true if the driver thinks it can open a connection to the given URL. Typically, drivers will return true if they understand the subprotocol specified in the URL and false if they don't. Our protocols start with jdbc:postgresql:

Specified by:

acceptsURL in interface Driver

Parameters:

url - the URL of the driver

Returns:

true if this driver accepts the given URL

See Also:

Driver.acceptsURL(java.lang.String)

getPropertyInfo

public DriverPropertyInfo[] getPropertyInfo(String url,
                                            Properties info)

The getPropertyInfo method is intended to allow a generic GUI tool to discover what properties it should prompt a human for in order to get enough information to connect to a database.

Note that depending on the values the human has supplied so far, additional values may become necessary, so it may be necessary to iterate through several calls to getPropertyInfo

Specified by:

getPropertyInfo in interface Driver

Parameters:

url - the Url of the database to connect to

info - a proposed list of tag/value pairs that will be sent on connect open.

Returns:

An array of DriverPropertyInfo objects describing possible properties. This array may be an empty array if no properties are required

See Also:

Driver.getPropertyInfo(java.lang.String, java.util.Properties)

getMajorVersion

public int getMajorVersion()

Specified by:

getMajorVersion in interface Driver

getMinorVersion

public int getMinorVersion()

Specified by:

getMinorVersion in interface Driver

getVersion

@Deprecated
public static String getVersion()

Deprecated. use getMajorVersion() and getMinorVersion() instead

Returns the server version series of this driver and the specific build number.

Returns:

JDBC driver version

jdbcCompliant

public boolean jdbcCompliant()

Report whether the driver is a genuine JDBC compliant driver. A driver may only report "true" here if it passes the JDBC compliance tests, otherwise it is required to return false. JDBC compliance requires full support for the JDBC API and full support for SQL 92 Entry Level.

For PostgreSQL, this is not yet possible, as we are not SQL92 compliant (yet).

Specified by:

jdbcCompliant in interface Driver

parseURL

public static @Nullable Properties parseURL(String url,
                                            @Nullable Properties defaults)

Constructs a new DriverURL, splitting the specified URL into its component parts.

Parameters:

url - JDBC URL to parse

defaults - Default properties

Returns:

Properties with elements added from the url

notImplemented

public static SQLFeatureNotSupportedException notImplemented(Class<?> callClass,
                                                             String functionName)

This method was added in v6.5, and simply throws an SQLException for an unimplemented method. I decided to do it this way while implementing the JDBC2 extensions to JDBC, as it should help keep the overall driver size down. It now requires the call Class and the function name to help when the driver is used with closed software that don't report the stack strace

Parameters:

callClass - the call Class

functionName - the name of the unimplemented function with the type of its arguments

Returns:

PSQLException with a localized message giving the complete description of the unimplemeted function

getParentLogger

public Logger getParentLogger()

Specified by:

getParentLogger in interface Driver

getSharedTimer

public static SharedTimer getSharedTimer()

register

public static void register()
                     throws SQLException

Register the driver against DriverManager. This is done automatically when the class is loaded. Dropping the driver from DriverManager's list is possible using deregister() method.

Throws:

IllegalStateException - if the driver is already registered

SQLException - if registering the driver fails

deregister

public static void deregister()
                       throws SQLException

According to JDBC specification, this driver is registered against DriverManager when the class is loaded. To avoid leaks, this method allow unregistering the driver so that the class can be gc'ed if necessary.

Throws:

IllegalStateException - if the driver is not registered

SQLException - if deregistering the driver fails

isRegistered

public static boolean isRegistered()

Returns:

true if the driver is registered against DriverManager